multimedia/gstreamer1-plugins-rust: fix build on armv7

Disable LTO to make the build fit into the virtual address space.
Same fix as for i386.

See also: 3e78ac41f17524591589aa00e50fddd20a2e8014
Approved by: portmgr (build fix blanket)
MFH: 2023Q4

(cherry picked from commit c7b5341dae6449af1d8fc1d7af47a2412ea2b5f6)